Electrical integrator



July 28, 1953 ,M. BEVIS ELECTRICAL INTEGRATOR Filed Aug. 12, 1946 INVENTOR. Murray Bear/ls A TTOR/VEY Patented July 28, 1953 U RTE ELECTRICAL IN TEGRATOR Murray Bevis, Oak Ridge, Tenn, assignor, by mesne assignments, to the United States of America. as represented by the United States Atomic Energy Gommission Application August 12, 1946, Serial No. 689,998

7 Claims.

This invention relates generally to an integrator for integrating the time intervals of occurrence of a condition which is, or may be, reproduced electrically, and, more particularly, to a device for indicating the total time of existence bf an abnormal condition, such as sparking, in electrical apparatus.

The specific device to be described herein has been developed for the particular purpose of indicating the total outage time which occurs during the operation of electromagnetic isotope separating apparatus. In such apparatus, as is well known, a beam of ions containing a plurality of isotopes is projected at a high velocity by means of an accelerating voltage through, and at right angl s to, an intense magnetic field. As a result, the original single ion beam is split into a plurality of component ion beams, each consisting solely of ions of a single mass weight, and these component beams may be separately collected at a receiver disposed at a focal point in their travel.

Normal operation of such isotope separating units is recurrently interrupted for short periods of time due to unavoidable sparking. The sparking is, of course, accompanied by a sudden drop in the accelerating voltage, and this, by affecting the velocity of projection of the ions, causes the ion beams to be deflected from their proper position on the receiver unit. During such sparking intervals therefore the isotope separating unit is ineffective for its purpose of separately collecting the isotopes. The summation of all such lost production time during a run is termed outage time, and for various control and accounting purposes it is desirable to have a quantitative knowledge of such time. The present invention is adapted to integrate or totalize the intervals of sparking which occur during a run so as to provide a quantitative indication of outage. A requirement of the design of such apparatus, of course, is that this integration be carried on accurately without regard to the intensity of particular sparks which occur.

Accordingly, it is an object of the present invention to provide a method of and apparatus for indicating the outage time due to sparking which has occurred in a run of an isotope separating unit of the electromagnetic type.

It is another object of the invention to provide apparatus for integrating the time intervals during which sparking has occurred in electrical apparatus.

Another object of the invention is to provide apparatus for integrating the total time of occurrence of a condition which may be reproduced as, or is accompanied by, an electrical phenomenon.

Other objects and advantages 9f the present til 2 invention will become apparent from the follow ing description, taken in connection with the accompanying drawing, wherein the single figure is a wiring diagram of the electrical integrator of the present invention.

Referring now to the single figure of the drawing, a voltage divider consisting of resistors R1, R2, R3, R4, and R5, connected together in series, is connected across a direct voltage supply, indicated as battery B. The various required potentials for the integrating device are obtained from various points on this voltage divider. The negative terminal of the voltage divider is connected to ground, as shown.

In an isotope separating unit of the electromagnetic type, the high intensity accelerating voltage is ordinarily supplied through a voltage regulator, and included within this regulator is a voltage divider across which the total accelerating voltage appears. Terminals I0 and ll of the present device may be connected across a portion of this voltage divider so that terminal I0 is connected to a grounded point on this voltage divider and terminal II is connected to a point at a small positive potential with respect thereto. Connected in series between terminals II and II] are a large blocking condenser C1 and and a large resistance Rs, as shown.

An amplifying vacuum tube, V1 which may be a pentode, as shown, is provided, having its cathode and suppressor grid connected to a point intermediate resistors R4 and R5 of the voltage divider of the present device. The control grid of vacuum tube V1 is connected to a point intermediate blocking condenser C1 and resistor R6. The screen grid of vacuum tube V1 is connected to a point intermediate resistors R3 and R4 of the voltage divider. The positive plate voltage for the vacuum tube V1 is obtained from a point intermediate resistors R1 and R2 of the voltage divider, this point being connected to the plate of vacuum tube V1 through plate resistor R7.

A second vacuum tube V2, which operates in the nature of an electronic switch, as will hereinafter be explained, is provided, this vacuum tube V2 having its cathode connected to a point intermediate resistors R2 and R3 of the voltage divider. The control grid of vacuum tube V2 is connected through limiting resistance R8 to the plate of vacuum tube V1. The screen and suppressor grids of vacuum tube V2 may be connected to the plate of tube V2, which plate is connected through plate resistor R9 and integrating condenser C2 to the positive terminal of the voltage divider power supply.

Two electronic circuits are connected in parallel across the integrating condenser C2, the first of these comprising a series circuit consisting of a small biasing battery E, a resistor Rllo, and a gas type voltage regulating tube V4. The second electronic circuit parallelling integrating condenser C2 consists of a series connection of a grid controlled gas type tube V3, which may be a thyratron, and an electromagnetic type counter, schematically indicated at K. The control grid of thyratron V3 is connected to the cathode of gas tube V4.

During normal operation of the isotope separating unit, that is when no sparking is occurring, a steady accelerating voltage exists in the unit, and, accordingly, a small steady direct voltage is maintained between the terminals Hi and II. This voltage, of course, operates to charge the condenser C1 through resistor R6 to an equivalent voltage, so that the control grid of vacuum tube V1 is normally at substantially ground potential. Since the cathode of vacuum tube V1 is maintained at a voltage slightly greater than ground potential by virtue of its connection to the slightly positive point intermediate resistors R4 and R5, the control grid of vacuum tube V1 normally has a slight negative bias with respect to the cathode. This bias is such that the vacuum tube V1 under these normal conditions is just conducting.

When sparking occurs in the isotope separating unit, the accelerating voltage suddenly drops by a large amount, carrying with it the potential of terminal I I. Accordingly, sparking in the isotope separating unit is accompanied by a negative pulse on terminal H, which pulse is transmitted through the condenser C1 to the grid of vacuum tube V1, thus cutting this tube ofi and rendering it non-conducting, The grid bias on tube V1 under normal, that is, non-sparking conditions, is such that a drop in the grid potential of only one or two percent will render the tube non-conducting. Since the pulses Which are impressed upon the grid of vacuum tube V1 due to sparking in the isotope separating unit correspond to a dip in the potential of the control grid by an amount well in excess of one or two percent, the vacuum tube V1 will be cut off completely immediately upon the occurrence of any subitantial sparking in the isotope separating un1 Due to the amplifying action of vacuum tube V1, negative pulses impressed upon its control grid due to sparking in the isotope separating unit appear as intense flat-topped positive pulses on its plate, and these pulses are transmitted and impressed upon the control grid of vacuum tube V2. The grid bias of vacuum tube V2 is normally such that this tube is non-conductin and the receipt of these flat-topped positive pulses cause the vacuum tube V2 to become conducting. The grid of vacuum tube V2 is driven so far positive upon the occurrence of these positive pulses that grid current flows in this vacuum tube through limiting resistor R8, thus providing a.

plate current limiting action within this tube. Due to the amplifying action of tube V1, and the limiting or clipping actions of tubes V1 and V2, the second tube V2 can be thought of essentially as an electronic switch controlling the flow of a constant plate current in its plate circuit in response to the receipt of a negative pulse upon input terminal I I substantially regardless of the intensity of this pulse. In this way, practically all sparks, which occur in the isotope separating unit, regardless of their intensity, are accompanied for their duration by a constant plate current flow in the plate circuit of vacuum tube V2.

Since gas tubes V3 and V4 are normally nonconducting, the constant plate current of tube 'sufliciently so that the potential across gas tube V4 will have reached its firing potential, whereupon this tube becomes conducting and the current through this tube begins to discharge condenser C2 through resistor R10.

The bias voltage on the control grid of thyratron V3 is normally such that the tube is nonconducting. However, as soon as gas tube V4 conducts, the surge of discharge current through resistor R10 causes the control grid of thyratron V3 to become sufficiently positive to allow this tube to fire. The resulting plate current of thyratron tube V2, as it flows through counter K, causes this counter to register once. The large amount of current which is permitted to flow in the circuit when thyratron tube V3 becomes conducting, is sufficient to instantaneously complete the discharge of condenser C2 and return gas tubes V3 and V1 to their non-conducting state. When this has happened, if plate current is still flowing through vacuum tube V2, that is, if sparking in the isotope separating unit has not yet been extinguished, the integrating condenser C2 will again begin to charge and the cycle will repeat itself. In this manner, the counter K will continue to register at equal intervals as long as sparking continues.

It is apparent that, for the duration or" a spark, a constant current flows into the parallel circuit which includes C2, V3, and V4111 its three parallel branches, respectively. In this parallel circuit, the charge on C2 determines the plate voltage of both V3 and V1. Since neither V3 nor V4 are conducting until the potential across C2 reaches the critical value at which V4. will fire, up until this time all of the current flowing into the parallel circuit must flow into C2 tending to charge C2 to this critical potential. When this critical potential has been reached, V4 fires thus causing the firing also of V3, as previously described. Since the external return circuit for each of these tubes is through the branch containing C2, C2 is immediately discharged by the tube currents. When C2 has been sufficiently discharged, the potential across it will no longer support the discharge through tubes V3 and V4, which tubes are thus rendered again non-conducting. The whole parallel circuit has then returned to its initial condition and the cycle repeats itself.

Thus, it will be apparent that the counter K will continue to count at a constant rate during all intervals in which sparking is occurring in the isotope separating unit, and that counting will be initiated immediately upon the occurrence of a spark and will continue until such sparking is terminated. Due to the above-described clipping or limiting action of tubes V1 and V2, the rate of counting will be independent of the intensity of the sparks.

The time constant of the integrating circuit may be adjusted as desired by varying the value of plate resistor R2 or the value of integrating condenser C2. It is desirable to have these values such that the counter K will register many times during the normal interval of duration of a spark in the isotope separating unit. The time constant of the integrating circuit may be adjusted such that the counter K indicates actual hours .and fractions of hours of outage or sparking time.

Since many changes in the above construction, and many apparently widely difierent. embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description, or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense. In particular, it will be stressed that the integrating device of the present invention is not limited in its application to intergrating the outage time of an isotope separating unit, but, in fact, 'may be employed to integrate the time intervals of duration of any condition which may be accompanied by a change in potential across input terminals l0 and H.

What is claimed is:

1. Apparatus for integrating the intervals of duration of electrical pulses comprising, a parallel circuit, said circuit having a condenser in one path thereof, a first gas tube in another path thereof, and a second gas tube and a counter arrangement in series in still another path thereof, said gas tubes being connected in their respective paths so that their respective plate-cathode currents form the respective path currents, and means responsive to said pulses for causing to fiow into said parallel circuit for the duration of said pulses a current which is substantially constant and independent of the intensity and duration of said pulses.

2. Apparatus for integrating the intervals of duration of electrical pulses of a random nature in respect to shape, amplitude and duration comprising, means for receiving said pulses, amplifying and clipping means responsive to said pulses for producing, for the duration of said pulses, concurrent fiat-topped current pulses of an amplitude substantially independent of the intensity of said input pulses, a condenser connected in series with the output of said amplifying and clipping means to receive the entire current of said flat-topped pulses and to be charged by said fiat-topped pulses, means connected in parallel with said condenser permitting the discharge of said condenser upon the attainment of a critical condenser potential, and means for counting the number of charge-discharge cycles experienced by said condenser.

3. Apparatus for integrating the intervals of duration of electrical pulses comprising, input means for receiving said pulses, a first vacuum tube normally biased barely above cut-ofi, means for supplying said pulses to the grid of said vacuum tube, a second vacuum tube having a limiting resistor in its grid circuit, means connecting the plate of said first tube to the grid circuit of said second tube, a condenser connected in the plate circuit of said second tube, means connected in parallel with said condenser permitting the discharge of said condenser upon the attainment of a critical condenser potential, and counting means responsive to discharge of said condenser.

4. Apparatus for indicating the total outage time due to erratic sparking of an electromagnetic isotope separating unit comprising, means for receiving a signal from said unit corresponding to the accelerating potential thereof, amplifying and clipping means responsive to variations of said signal from a normal value for causing, for the duration of said variations, a current flow the intensity of which is substantially independent of the duration and intensity of said variations, a condenser connected to be charged by said current, means connected in parallel with said condenser permitting the discharge of said condenser upon the attainment of a critical condenser potential, and counting means responsive to discharge of said condenser.

5. Apparatus for integrating the intervals of duration of electrical pulses comprising a parallel circuit having three parallel branches, the first of said branches including a condenser, the second of said branches including a voltage source, a resistance, and a first gas tube, in series, and the third of said branches including a second gas tube and a current actuated counter in series, said gas tubes being connected in their respective branches so that their respective plate-cathode currents form the respective branch currents, said second gas tube having a grid for control thereof, a connection between the grid of said second gas tube and a point intermediate said resistance and said first gas tube, and circuit means responsive to said pulses for causing to flow into said parallel circuit, as a whole, for the duration of said pulses, a current of substantially constant amplitude.

6. Apparatus for integrating the intervals of duration of electrical pulses comprising, a parallel circuit, said circuit having a condenser in one path thereof, a gas tube in a second path thereof, and a grid controlled gas tube and a counter arrangement in series in a third path thereof, said gas tubes being connected in their respective paths so that their respective plate-cathode currents form the respective path currents, said circuit including means, including a connection between the control grid of said grid controlled gas tube and said second path, for firing said grid controlled gas tube in response to the firing of the gas tube in said second path, and means responsive to said pulses for causing to flow into said parallel circuit for the duration of said pulse a current which is substantially constant and independent of the intensity and duration of said pulses.

7. Apparatus for integrating the intervals of duration of electrical pulses of a random nature in respect to shape, amplitude, and duration comprising, means for receiving said input pulses,

amplifying and clipping means responsive to said pulses for producing for the duration of said pulses concurrent fiat-topped current pulses of an amplitude substantially independent of the intensity of said input pulses, and a three path parallel circuit connected in series with the output of said amplifying and clipping means to receive the entire current of said fiat-topped pulses, said circuit having a condenser in one path thereof, a first gas tube in another path thereof, and a second gas tube and a counter arrangement in series in still another path thereof, said gas tubes being connected in their respective paths so that their respective plate-cathode currents form the respective path currents.

MURRAY BEVIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,762,712 Charlton June 10, 1930 1,933,976 Hanson Nov. 7, 1933 1,995,890 Lord Mar. 26, 1935 2,113,011 White Apr. 5, 19 8 2,272,998 Bjornson Feb. 10, 1942 2,413,440 Farrington Dec. 31, 1946 2,422,766 Alexander June 24, 1947 OTHER REFERENCES 'rheory and Application of Electron Tubes, Reich, published 1944, McGraW-Hill Co., New York, N. Y. (716 pages), page 457, lines 1-3, Figures 12-12 and 12-13; page 621, Figures 15-35. 

